RFID tags for identifying goods are well known. They can be applied to either the goods themselves or to packaging for the goods. RFID tags typically comprise an integrated circuit or chip and an antenna coupled to the chip. Information regarding the goods is stored upon the chip. For example, this information can include identification information, manufacturing information (such as what manufacturing processes have already been performed and/or what manufacturing process is to be performed next), customer information, or shipping information. RFID tags can be formed upon labels to facilitate their application to the goods or packaging.
The antenna typically comprises a plurality of conductive traces formed upon a substrate, such as the label. The antenna facilitates communication between the chip and an RFID reader and/or writer. Information is read from an RFID chip by first interrogating the chip with a reader. The reader transmits a signal that is picked up by the antenna and is then communicated to the chip. The chip subsequently responds by communicating a signal to the antenna that is then transmitted to the RFID reader.
The information can be read by either a hand-held RFID reader or a stationary RFID reader. Hand-held RFID readers can be used in warehouses, for example. In a warehouse, an RFID reader can be used to locate a desired item (having an RFID tag) from among many similar items.
Stationary RFID readers can be used in manufacturing processes. For example, they can be used to determine what manufacturing process is to be performed next on an item passing along a conveyor. Thus, an RFID reader can be used to determine what color an item is to be painted or what accessories are to be added thereto. Such information can be used to determine where in a manufacturing plant the item goes next and thus facilitates automation of the manufacturing process.
One problem with contemporary RFID readers is that they tend to be undesirably indiscriminate with regard to which RFID tag is being read. Although they are somewhat directional with respect to how the beam is transmitted therefrom, they are not completely directional. The transmitted beam has some amount of spread and is thus capable of reading other RFID tags that are proximate the desired RFID tag. Generally, if an RFID reader is pointed directly at the desired RFID tag, it is much more likely to read only that particular RFID tag. However, if the RFID reader is slightly off (not well aimed), then it may read a nearby RFID tag instead. Thus, it is sometimes difficult to know which item's RFID tag is being read.
For example, if a person is looking for an item in a warehouse, the RFID reader may indicate the presence of the desired item on a shelf. However, if there are other similar items nearby, then the user may have difficulty determining which of the items is the desired one. As such, it is desirable to provide a way to better aim RFID readers or otherwise determine when they are pointed at a selected RFID tag.